AVS 46th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI-TuP

Paper BI-TuP1
Characterization of Adsorbed Protein Films by Static Time of Flight Secondary Ion Mass Spectroscopy (ToF-SIMS)

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: M.S. Wagner, University of Washington
Authors: M.S. Wagner, University of Washington
J.B. Lhoest, University of Washington
D.G. Castner, University of Washington
Correspondent: Click to Email
The development of effective biomaterials requires knowledge about the composition and structure of the adsorbed protein film that is formed upon implantation of a biomedical device in the body. Static Time of Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) is a powerful technique for probing the molecular structure and composition of the outermost layers of a surface, making it an ideal technique for characterizing adsorbed protein films. Previous static ToF-SIMS studies of adsorbed protein films have shown the data obtained are complex fragmentation patterns arising from the amino acids present in proteins. To efficiently utilize all the information in these complex spectra requires multivariate analysis methods. We have used Principle Component Analysis (PCA) and Partial Least Squares (PLS) regression of the static ToF-SIMS data to characterize the composition of adsorbed protein films on mica and Teflon surfaces. PCA was used to differentiate the pure films of various plasma proteins (albumin, fibronectin, fibrinogen, etc.). PLS regression was used to quantitate the surface composition of protein films resulting from the competitive adsorption of binary protein mixtures comprised of albumin/fibronectin and albumin/Immunoglobulin G. For the albumin/fibronectin mixtures it was found that solutions containing more than 20% fibronectin produced adsorbed protein films that appeared to be pure fibronectin. The static ToF-SIMS results could be quantified by calibrating them with radiolabeled protein adsorption results. The overall aim of this research is to generate of a ToF-SIMS spectral database that can be used to determine the composition and structure of multicomponent adsorbed protein films with static ToF-SIMS.